Process for making sulphur from sulphur dioxide



G. C. HOWARD.

PROCESS FDR MAKING SULPHUR FROM SULPHUR DIOXIDE.

APPLICATION FILED SEPT.9, I9I8- RENEWED NOV. 28.192I. Lm@

Patented May 23, w22.,

I l I gm L1.

GUY C. HWD,

dz REFJINJIING CU., A CORPORATION OJE JERSEY.

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iguanas.

Application filed beptember 9, 191%, Serial No. 253,157. Renewed November 28, 1921. Serial No. l.

To all whom. I? may concern Be it known that l, GUY C. HOWARD, a citizen of the United States, and resident of Tacoma. in the county of Pierce and State lof lVashington, have invented certain new and useful Improvements in Processes for Making Sulphur from Sulphur Dioxide, of which the following is a specification.

The invention relates in general to a process for recovering sulphur from sulphur dioxide gasl and specifically relates to a process :forl recovering sulphur from metallurgical gases containing sulphur dioxide.

lllhe invention contemplates an improvement in the known process of subjecting sulphur dioxide gas to the reducing action of incandescent coke or similar reducing agent.

rllhe primary object of the invention is to provide a simple process for producing sul,-

'phur in large quantities economically on a `commercial scale.

incidental to this general object it is among other desideratum to maintain such conditions as will eliminate Secondary reactions detrimental to the process and to carry out the process with a view to adapting it to establish metallurgical conditions so that it may be operated with such economy to sustain commercial life. s

Une approved process fory carrying the object of the invention consists in l. Cooling and removing the flue dust and metallic fumes from the metallurgical gases.

2. bso'rbing the sulphur dioxide in water or other suitable solvent thereby separating it from other gaseous constituents.

3. Driving od' the sulphur dioxide and some water vapor from the absorption liquor by heating it practically to boiling temperau I ture.

4l. Cooling the sulphur dioxide gas to remove part of the water vapor and then passing it through concentrated sulphuric acid or by'other suitable means to completely dehydrate the sulphur dioxide gas. y

5. Liquefying the sulphur dioxide gas by subjectin it to pressure and refrigeration.

6. Stormg the liquefied sulphur dioxide in a suitable tank or container.

7. Feeding the liquid sulphur dioxide to expansion coils in which it is volatilized as a sulphur dioxide gas of 100% purity and free from/moisture.

Specification of Letters Patent.

rarement nay aa, iaaa.

8. Mixing this pure dry sulphur dioxide with a regulated amount of atmospheric air whlch may or may not be cle-hydrated dependmg on its realtive humidity.

9. Passing this mixture through a suitable equipment whereby it is preheated to a certain extent by the hot exitgases from the reduction furnace next referred to.

l0. Passing this-heated gas mixture into a reduction furnace cont-aiming incandescent cokeor equivalent and in which the sulphur dioxide is reduced to sulphur by contact with the incandescent coke.

11. Causing the exit gases ofthe furnace to pass through the above preheater whereby their heat is largely transferred to the incoming gas mixture.

12. Thence passing the cooled exit gases through a settling chamber in which the sulphur is collected in part and finally passing through bags or other filtering device to recover the balance of the sulphur.

Por the purpose of illustrating a plant for carrying out some of the steps ot' the above outlined process, reference is made to the accompanylng drawings which show, diagrammatically, a new arrangement of conventional apparatus.

lt is to be understood that the first five steps hereinbefore outlined can be performed with the usual apparatus now in general use and that the concentrated, de-hydrated and liquefied sulphur dioxide is admitted to a storage tank A. rPhe liquefied sulphur dioxide is discharged therefrom to a set of expansion coils C through a controlling expansion valve B. The coils are' of the usual double pipe expansion coil setscommon in `at least one pipe chamber of the double pipe coil."v rl`his utilization of the expansion coil latent heat of evaporation of thev liquid sul-` phur dioxide and also supplies a refrigerant to the-air suppliedto` the fan E. By eithe` of these meansthe-moisturecontents of theair isireduced to a minimum.- A valve F iu` the discharge lineal of, the fan provides a v'means for regulating the volume ofair de-i` g lli'vered by the fan'- into the mainf G. The- \sar1ly hlgh, 1t can bejreduced and 1f 1t gets i sulphur dioxide from vthecoil VC and the 'air 'from the fan E are mixed in any desired 'v proportion'by means of the regulating valves enana r.

Main Gr leads-the gas mixture through a -coil` ofpreheating pipes H shown in broken lines located in a reheater' chamber N. The

gases slightly cated in" their passage through the pipes H are lead hence through a mai-n 'J to the interior of -a reductionY furnace AK. -This furnace is preferably a furnaceof a gas producer type, with a hopperL for feeding coke thereto and with an exit Hue M leading to the preheater N. The furnace.: K contains au incandescent .coke bed through which the` sulphur-dioxide j and air mixture from the main-J passesand in4 which-the sulphur dioxide is reduced to i elemental sulphur. v The free: oxygen of the air within the furnace combines with the' carbon present'to supply an increment of heatl necessary to sustain suitable furnace c j temperature-to give completere-action. The exit gases from the -furnacecontain essenti- 35 ally, pure sulphur vapor, carbon dioxide' "and nitrogen. These Agases pass through the `preheater chamber N wherein their heat is "l, largely transferred to the incoming gas. mixture carried in pipes H.' From chamv 40 ber'N the cooled exit gases pass to the settling chamber O wherein the sulphur largely settles out. A fanP connected to the cham# lber O draws the gases therefrom and delivers it 'to `a bag or other filteringl dev-ice Q, in. which the remainder of the sulphur is Y recovered. The gaseous constituents of the air or into other gas handling apparatus.

- In operation, and assuming that there is pure liquefied sulphur dioxide in the tank a coke fire is started-in furnace K-and' built upby admitting air-from fan E untit' a suitable zoneI of .incandescent'cokeis -es,

:dioxide gas and air enter main 'G in aprei Adetermined ratio." Fan P is actively disposedl'andmaint'ains a desired draft through the furnace andl subsequent vequipment sufcientto carry off the exit gases-'from the furnace.

Thereaction between sulphur dioxide and the incandescent coke' depends primarily on the temperature of the incandescent coke too low for complete reaction it can be increased by suitably adjusting the valves.

The time of contact of the gases is determined bythe volume of sulphur dioxide air mixture fed to the furnace and by the volume of the incandescent coke zone present in the furnace.

l Coke is fed to the furnace as needed and j the ashes removed either periodically or continuously. The sulphur produced is removed from the preheater N, from the chamber O and from the bag, Q, eithercontinuously or'periodically by suitable means.

Ascarried out in this manner the process is Continous and under complete control.

By means of a process such as is herein outlined the moisture contents in the gases going to the reduction furnace is held to a minimum which' condition facilitates tempera-ture control of the furnace and prevents secondary reaction which would otherwise complicate the process, if the moisture contents of the gases were not so regulated. It is understood that whilethe step of liquefying the sulphur dioxide gas is not vital to the process, it has the advantage in that it further insures the purity of the resulting j sulphur dioxide gas supplied to the reducing furnace and during the step of vaporizing supplies a convenient refrigrating agent to reduce the moisture contents of the atmospheric air in cases where the moisture contents is high. In the step ofl subjecting the incoming gases to the heat `action of the products of vcombustioni from the reduction furnace, a exit gasesescape through the bag into the h eat economy-is effected. A small increment of heat must be supplied in practice to supplement the heat of reaction of sulphur dioxide and coke in order to sustain the necessary furnace temperature to give complete reaction. This is required because of certainheat losses due to radiation and to heat not recovered from the exit gases.

The simplest method of supplying this additional heat isby burning coke inside the furnace with the oxygen in the air admitted with the pure sulphur dioxide gas.

Havingv thus described my invention, I claim 1 1. VIn the art offproducing sulphur from sulphur dioxide gas, the process which consistsin li'quefying the gas, vapor'izing' the liquefied gas thereby supplying4 a.y refrigerv.ant agent, 'subjecting air to the action of Lampes gas and subjecting the mixture to a reducing.

action. y

2. -In the art of producing `sulphur from orming a refrigerant,

- subjecting air to the action of said refrigerant thereby to reduce the moisture contents of the air, mixing the refrigeratedairvvith the vaporized sulphur dioxide and subjecting the mixture agent. f

3.. In the art of producing sulphur from liquid, sulphur dioxide,` the process which to the action of a reducing consists in' vaporizing the liquid, subjecting air -to the action of a refrigerant agent, mix-y phur dioxide gas thereby forminga sulphur ing the refrigerated air -With'the vaporized sulphur dioxlde gasv and reducing the mixture.l f

Ll. In the art of forming sulphur from liquefied dehydrated sulphur dioxide, the

process which consists in volatilizing the liquefied sulphur dioxide to Jiorni pure sul-l pl'iur dioxide gas substantially free of air,

fmixingthe volatilized sulphurdioxidewith g atmospheric air in regulated quantities and subjeetingthe'mixture to a reducing action. 5,"In the art of forming sulphur from processwhich consists .in volatilizing the dioxide vgas having a lovv moisture content,

4 mixing said sulphur dioxide gas .with atmospheric air! in "regulated quantities, sub- -jecting the mixture of sulphur dioxide and( v airto-a reducingaction and separating `the resulting sulphur from the remainingfgases..

7' 6,. In the art of^forlninl sulphur from.4 concentrated, dry sulphur di process which consists in mixing 0air having oxide gas, the

July, a; n. ,1918.

a known vapor content With the dry gas in regulated proportions tocontrol the amount of Water present in fthe mixture, vpreheating the mixture, subjecting the preheated mix- -ture to the actionl of incandescent carbon, liquid sulphur dioxide, the 'process whichv consists .in vaporizin the vliquid sulphur di- 'oxide incidentally utilizing the heat produced to supply thev necessary heat to give the preheating step a desired temperature. and at the same time to cool the gases delivered from the'incandescent carbon-reaction-step and finally permitting the sulphur to settle from the cooled gases.. j i. v

7. In the art of reducing sulphur from a mixture of gases containing sulphur dioxide, the process which includes the steps of separatin the sulphur dioxide as a de-hydrated liqueedgas to purify the same, vaporizing the liquid sulphur dioxide to form a cold Vsulphur dioxidegas having a'loW moisture content and subjecting the cold vaporized gas to a' reducing action in the presence of air' substantially free of Water;

8. In the art of reducing sulphur from a mixture of gases containing sulphur dioxide, the' process which includes the steps of de-hydrating the sulphur dioxide present to remove any Water, adding substantially mixture of sulphurdioxide andair and subjecting the mixture to a reducing action substantially free of the presence of Water.

9. In theart ofproducing sulphur from gases vcontainingV sulphur dioxide gas, the process which consists first in drying the sulphur dioxide gas, and then subjecting a regulated amount ofthe dry, sulphur dioxide gas, together with. a' regulated,A amount oit atmospheric air which hasa low vapor content to a reducing action.l

y Signed at Tacoma, inthe county of Pierce and State of Washington this fifth dayof.

nur enormen.

dry air to the sulphur dioxide to form a 

